GREEN: the new Global Radiation Earth ENvironment model (beta version)

Abstract

Abstract. GREEN (Global Radiation Earth ENvironment) is a new model (in beta version) providing fluxes at any location between L∗= 1 and L∗= 8, all along the magnetic field lines, for all local times and for any energy between 1 keV and 10 MeV for electrons and between 1 keV and 800 MeV for protons. This model is composed of global models (AE8 and AP8, and SPM for low energies) and local models (SLOT model, OZONE and IGE-2006 for electrons, and OPAL and IGP for protons). GREEN is not just a collection of various models; it calculates the electron and proton fluxes from the most relevant existing model for a given energy and location. Moreover, some existing models can be updated or corrected in GREEN. For examples, a new version of the SLOT model is presented here and has been integrated in GREEN. Moreover, a new model of proton flux in geostationary orbit (IGP) developed a few years ago is also detailed here and integrated in GREEN. Finally a correction of the AE8 model at high energy for L∗ < 2.5 has also been implemented. The inputs of the GREEN model are the coordinates of the points and the date (year, month, day, UTC) along an orbit, the particle species (electron or proton) and the energies. Then GREEN provides fluxes all along the given orbit, depending on the solar cycle and other magnetic parameters such as L∗, Bmirror and Beq.

Surface Ionizing Dose for Space Applications Estimated With Low Energy Spectra Going Down to Hundreds of Electronvolt

“…Different environmental models describing the radiation belts of the earth exist. The reference models in all international standards are still the NASA AE8 and AP8 [21] models, respectively for electrons and protons, even if some updates (AE9, AP9) [23] and new models have been proposed since (GREEN) [24]. The low energy cutoffs of both models are respectively 40 keV for electrons (AE8) and 100 keV for protons (AP8).…”

“…NASA provides the AE9/AP9 [22], [23] model. ONERA with the support of the French Space Agency (CNES), has also developed the GREEN [24] model, with cutoff energies of 200 eV. In addition, radiation transport models valid down to a few eV for electrons and a few tens of keV for protons have been recently developed and made available to the space community [25]- [33].…”

A Proton Sensor for Energies From 2 to 20 MeV

“…AP-8 and AE-8 models [21] [22] are considered to compute differential fluxes at several McIlwain L-parameter values, which are the distances expressed in Earth-radii of the apex of magnetic field lines. After [23] [24] and [25] a correction factor is applied to electron fluxes with energies greater than 800 keV at L < 2.5 returned by the AE-8 model: AE-8 fluxes are divided by a factor of 100 for < 2.5 and for energies greater than 800 keV (in other words, electron fluxes with energies greater than 800 keV are negligible below L=2.5). Count rates are calculated for all deposited energy channels along the magnetic equator.…”

Impact of Earth’s Magnetic Field Secular Drift on the Low-Altitude Proton Radiation Belt From 1900 to 2050

“…This new long-term assessment of the MePA drift versus L shells (1<L<2.5) and altitudes (400 km<altitude<1400 km) has next been implemented in the OPAL model [1]. It will be released to the public via the GREEN-p model [6] and implemented in the OMERE tool [16].…”

“…The model accounts for the secular drift of the Earth's main magnetic field based on the International Geomagnetic Reference Field (IGRF) and National Oceanic and Atmospheric Administration (NOAA) data from 1980 to 2012 and for the solar cycle modulation impact of the proton flux. Currently two main initiatives to propose new global specification models for the Earth radiation belts are ongoing: Aerospace Electron 9/Aerospace Proton 9 (AE9/AP9) [4] [5] and GREEN [6].…”